Ventilation costs

Heating, cooling, and ventilation of premises require some sort of energy. The data shows that approximately 50% of the energy is required for heating and cooling, while ventilation of premises uses the remaining 50%. If we ventilate the premises by opening windows, we lose nearly the entire energy that has been brought into the room (we refer to this as heat losses). To re-establish the desired indoor temperature conditions we need to heat or cool the room, which – in turn – leads to additional costs and increased CO2 emissions.

If we remain focused on the fact that about a half of generated energy is spent on heating and cooling, while the other half is spent on ventilation, installation of a ventilation system can lead to high potential savings. If we select the ventilation system with a high heat recovery rate, heat losses and ventilation costs will be lower. E.g. in case of a ventilation unit with 95% efficiency at the maximum air flow, our ventilation costs would decrease by 95%. Here is the calculation:

Renovated buildings, where renovation includes the installation of energy efficient windows, façade and roof, use about 50kWh/m2 of energy for heating, cooling and ventilation. If we take a room of 60m2, the energy use will amount to about 3000 kWh, of which 1500 kWh will be used solely for ventilation. If we install a suitable ventilation unit with a 90% heat recovery rate (at the maximum air flow), the ventilation of the room will require 10% of the initially required 1500kWh, i.e. 150 kWh. If 1 kWh costs EUR 0.13, this means our ventilation costs will amount to EUR 19.5 instead of EUR 195 – heat losses will no longer amount to 50%, but they will drop to a mere 10% (as the unit has a 90% heat recovery rate).